FRACTIONS
State fractions in text in the simplest possible way, usually in words or decimals. Do not combine a figure and a spelled-out number.
Generally spell out half, third, quarter:
a half or one-half
two and a half
Spell out simple fractions unless used in pairs or in dimensions, or fractions that are cumbersome:
seven-eighths
4¾ or
3½ by 4½ feet
11½
1/7000 (do not use th) of a pound
a hundredth or one-hundredth
thirty-nine millionths of an inch
two-billionths
Do not use commas in any part of a fraction with fewer than five digits.
Connect numerator and denominator with a hyphen unless either already contains a hyphen:
one-ninth
one thirty-second
forty-five hundredths
twenty-one thirty-sixths
Note the difference:
three-hundred thousandths (300/1000) and
three hundred-thousandths (3/100,000).
A fraction may be singular or plural depending on the intention of the writer. Generally the object of the preposition of following the fraction governs the verb:
Two-thirds of Nepal's population lives in these heavily farmed valleys; two-thirds of them live here.
Use figures for all numbers that contain decimals:
3.4 inches of rain
22.25 inches of snow
a 12.5-billion-dollar deficit
If the amount is less than one, the unit of measurement is singular:
.33 inch (not inches) a day.
If the figure is a one-digit decimal, use a zero before the point:
0.3 inch a day